In a field that the invention does not concern capping devices of this type are known in which the insert is first added to and permanently fixed inside the outer cap, before thereafter placing on a container neck to be capped the combination consisting of the assembly of this insert and this outer cap. U.S. Pat. No. 6,044,995, GB-A-1 316 162 and FR-A-2 219 081 provide examples of this: in all cases, the proposed inserts are a priori incapable of being added to the free end of a container neck and retained in sealed manner if the outer cap of the device is not conjointly present with the insert.
In contrast to what has just been described, the invention specifically concerns caps for which the insert is designed to be fitted to the neck independently of the outer cap so that this insert is advantageously placed on the neck before the outer cap is fitted afterwards. EP-A-1 254 848 provides one example of such a cap. The preamble of the appended claim 1 is based on EP-A-1 254 848.
The benefit of such a cap structure is linked to sanitary considerations: accordingly, in EP-A-1 254 848, after a container is filled in an aseptic filling enclosure, the insert alone can be easily fitted, also in this aseptic enclosure, so as to hermetically seal the neck without biological contamination of the content of the container, before the container is transferred into a non-aseptic bottling area, in which the outer cap is fitted to the neck already plugged by the insert.
This being so, current capping devices, including that proposed by EP-A-1 254 848, do not provide a satisfactory solution for situations where, when filling the container, the exterior face of the neck thereof is soiled by the product with which the container is filled. Indeed, in the event of overfilling, product overflows the neck and runs down its exterior face. Runs can also be produced in the event of leaks or splashes originating from the filling system. The situation is the same for all products tending to foam up, such as beer. Moreover, for beer in particular, the formation of foam is even intended so that this foam occupies all of the free volume of the neck, above the surface of the beer, and thus expels the air initially present. In this case, considerable runs of foam systematically occur and therefore significantly soil the exterior face of the neck. The residues of the liquid, left by these runs, often lead to biological contamination of the neck of the container by yeasts or the like.